Both over-the-counter and prescription medications can sometimes produce emotional or mental side effects. Too, as the number of manufactured drugs increases, the potential for interactions among different medications increases greatly. Certain drug interactions produce symptoms of marked agitation, restlessness, and anxiety. Furthermore, patients who have regularly taken a particular medication may sometimes find that it begins to cause unexpected side effects. "False senility" in elderly patients, for example, is often induced by medication; when the medication is stopped, the undesirable symptoms disappear. DRUG ADDICTION AND ALCOHOLISM Both are runaway habits that can cause nervousness and overreactions to small crises. Ironically, individuals are usually first attracted to narcotics or alcohol in order to obtain _relief_ from anxiety. But once the addictions have become firmly established, emotional symptoms of depression, irritability, sudden changes of mood, nervousness, and paranoia are common, as are memory loss and difficulty in concentrating. Caffeine is an emotionally habit-forming drug. Real addiction--i.e., physical dependence with withdrawal symptoms--appears to be rare. Nevertheless, coffee, tea, and cola drinkers can become emotionally dependent on caffeine. The drug is a {109} frequent cause of chronic nervousness in habitual caffeine users. Smoking is a habit that causes a person to lose approximately 5½ minutes of life expectancy for each cigarette smoked. Beyond this, smoking is also a common but unrecognized cause of chronic nervousness, in spite of the fact that many smokers believe smoking will help steady their nerves. By now it should be evident that the two main signs of emotional distress--anxiety and depression--can sometimes be the symptoms of undetected physical disorders. Especially in cases of severe anxiety or depression _without_ physical complaints, both therapists and clients tend to overlook the possibility of physical illness. It is true that, at present, the majority of such cases cannot be traced to underlying physical causes; they are therefore treated by means of psychotherapy or psychiatric drug therapy. As medicine and biochemistry develop, however, mental and emotional complaints are increasingly being understood in more physical terms.